Of course caffeine can make you underestimate how wasted you are. But you probably knew that already.

So it's 11 am on a Sunday, and you're about to head out for a bagel when your roommate walks in, smelling like a leftover death wish and mumbling something about throwing a cinderblock through a Pepsi machine because the Four Loko made him do it. Also, he is naked.

Point is, we all know that guy. And while nobody wants to head home early because he can't hang with the crowd, we all know that knocking back a gallon of Four Lokos at your neighborhood rager is a good way to make sure you try to fight your ex-girlfriend's new boyfriend and then wake up under a capsized Dumpster inhabited by irate raccoons.

Ever wonder why? It's because energy drinks—and the caffeine in them—can also mask the effects of drinking alcohol (like getting tired) and increase your risk of injury, according to a new study published Tuesday in the Journal of Studies on Alcohol and Drugs. Put another way, caffeine actually makes you forget that you're drunk.

In the study, researchers analyzed peer-reviewed journal articles that focused on energy drinks and alcohol. They found that over 76% of those studies showed evidence of a direct link between the use of energy drinks mixed with alcohol, and a greater chance of getting hurt (anything from a car accident to getting into a physical altercation) compared to drinking just alcohol alone.

"Usually when you're drinking alcohol, you get tired and you go home," says Audra Roemer, M.Sc., lead author on the study. "Energy drinks mask that, so people may underestimate how intoxicated they are, end up staying out later, consume more alcohol, and engage in risky behavior and more hazardous drinking practices."

And look, we get it: You're gonna live your life. But if you're trying to stay jacked up when you're going out, it's probably better to just nap before you head out, and then rally, college-style. Pace yourself. Get a cab home.